Many geranyl compounds having 1,5-diene structure are present in vivo, and are known as in vivo precursors of substances having polyene structure and exhibiting various physiological activities. These substances having 1,5-diene structure and polyenes derived therefrom invariably start from mevalonic acid and biosynthesized.
I noticed, as such geranyl compounds having 1,5-diene structure, germanic acid or geranylamine, and furthermore mevalonic acid which is the base for biosynthesis of polyenes, synthesized various derivatives of germanic acid or geranylamine and mevalonic acid and investigated their physiological activities, in particular, antitumor activity and toxicity, and have come to complete the present invention.